H, C. Bolton—Action of Light on Uranium. 213 
The remaining experiments were made with unsalted non- 
albumenized papier de saxe. The prints were well washed be- 
fore development. An unvarnished negative was used. 
No. 2. (March 11, 1869.)—Sensitized 1st with formic acid, 
2nd oxyfluorid of uranium and sodium, Exposed one hour, 
Fixed (?) by washing. A .weak print, green when first ob- 
tained, turned yellow on exposure. 
Wo. 3. Sensitized with oxyfluorid of uranium and sodium 
mixed with glycerine. Exposed one hour—a violet print, which 
turned lemon-yellow on exposure. 
o. 4, Sensitized with Ist, oxalic acid; 2nd, oxyfluorid of 
uranium and potassium. Exposed 15 minutes, Developed with 
ferricyanid of potassium—fixed by washing. A red picture. 
No.6. Sensitized with citrate of uranium and ammonia. Ex- 
posed 10 minutes. Developed with ferricyanid of potassium. 
A clear red picture. 
No.7. Sensitized with Ist, oxalic acid ; 2nd, oxyfluorid of 
No. 8. Sensitized with oxyfluorid of uranium and sodium 
mixed with formic acid. Exposed 1 minute. Developed with 
Vo. 12. Sensitized with nitrate of uranium mixed with gly- 
cerine. Exposed 2 minutes, Developed with ferricyanid of 
potassium. An inferior red print. _ : : 
No. 13. Sensitized with nitrate of uranium mixed with glyc- 
erine. Exposed 2 minutes. Developed with nitrate of silver 
and fixed with hyposulphite of soda. A fair print. é 
No.14. Sensitized with oxyfluorid of uranium and sodium 
mixed with glycerine, Exposed one minute. Developed with | 
nitrate of silver and fixed with hyposulphite of soda. An ex- 
cellent well defined picture. 
